最新刊期
卷 ， 期 5 ， 1998
- 摘要：Poly( p benzamide) can be dissolved in DMSO NaH system,giving a homogenious solution of polyanion.After evaporating DMSO and using some solvents for regenerating polyanion into poly( p benzamide),regenerated films were obtained.By X-ray diffraction,the dried films at room temperature are amorphous.Heat treating at 130℃ for 14h did not influence the structures of the films very much,but after heat treating at 250℃ or 300℃ for 30s,the structures of the films changed from amorphous state into modification 1 or modification 2 of crystal.Comparing with modification 1,modification 2 had reflections at d=0.49nm and d=0.28nm strongly,but the reflection corresponding to the reflection at d=0.31nm ini modification 1 disappeared or could not be observed clearly.
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发布时间：2021-03-19 - 摘要：The on line analysis on morphology for immiscible polymer blends during molten processing has been completed by small angle light backscattering.A typical polymer system,as poly( cis butadiene) rubber is used.The structure evolving with change of blending time and different blending speeds was discussed.The structure parameters of blend,as correlation distancd a c and mean chord length D ,with on-line system were calculated,and the mean size of disperse phase in the blend was calculated by scanning electron microscope.The variation of mean size of disoerse with mixing time was similar to the result of the correlation distance ac and mean chord length D.And some theories were used to analyze experiment data.
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发布时间：2021-03-19 - 摘要：The self avoiding walk(SAW) tail chain on diamond lattice was studied in this work.The permitted conformational number C(D) 1(N) and the mean square end to end distance h (D) 1(N) 2 as function of the chain length N for such a model tail chain were obtained by the computer simulations including the exact enumeration and Monte Carlo method.These two basic quantities obeyed the relations deduced from the scaling law.The critical exponents and the lattice indexes obtained from C (D) 1(N) and [h(D)1(N)]2 were given by fitting the data of the computer experiments.It was shown that there is a certain extension in the size in the direction normal to the wall for the SAW tail chain as well as for the normal random walk tail chain.The normal component of the mean square end-to-end distance is almost as twice as the parallel component of the short chain SAW.However,as N→∞,the effect of the wall on the chain conformation becomes weak because of the self-avoiding behavior for the model.It was identical with the result obtained from the SAW on the simple-cubic lattice.
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发布时间：2021-03-19 - 摘要：The unit cell parameter of polypropylene crystallized with different method and condition was studied:curves of wide angle X-ray diffraction(WAXD) are determined by stepwise scanning method,X ray multi peaks resolution program and simulation program of unit cell parameter developed by the general inverse matrix method are used as data processing of determined results.It is shown that effect of crystallization condition on the unit cell parameter is marked.Crystal density of samples decrease in order:crystallized in 145℃ for 5h (0.970g·cm-3)>quench(0.950g·cm-3)>orystallized out from solution (0.937g·cm-3).Thermal behavior of these samples are inverstigated by differential scanning calorimeter.It is shown that the melt peak temperature I relaties to crystal density.
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发布时间：2021-03-19 - 摘要：Polymer dispersed liquid crystal samples have been fabricated by using photopolymerization induced phase separation method at different cure temperatures.Liquid crystal textures formed in droplets were investigated under optical microscopy in its ON state and OFF state.A simple method of determing the inflence of cure temperature on phase separation degree has been studied by measuring the phase transition temperature of those droplets, and the phase separation structure has been observed by using scanning electron microscopy.Results show that in a suitable cure temperature range,the average diameter of liquid crystal droplets will become smaller and more uniform as the cure temperature was increased,and also the formed liquid crystal droplets will become more pure and the matrix morphology can be formed from"normal"to "reverse" mode.Those results will be given and discussed.
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发布时间：2021-03-19 - 摘要：According to the equation of cluster dynamics in reacting system,combining with the kinetics equatin of BA VAc emulsion copolymerization in batch and semi continuous process,the development of particle morphology was simulated.The results are as follows:1.For the batch process,when VAc homopolymer is beginning,some clusters are randomly distributed in the copolymer latex particle.With the increase of time,the clusters,which were growing by both polymerization and coagulation,migrated toward the surface of particle.At last, a single core-shell structure is formed.2.For the semi-continuos process,the final particle morphology revealed microphase separation structure,the faster the import speed of monomers,the greater the separated degree.During the slowest import speed,a multi-core-shell structure is formed.These simulation results are in agreement with the literature reports.
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发布时间：2021-03-19 - 摘要：Ketonic type polymers can be obtained by acylating dibenzo 18 crown 6 with aliphatic dibacic acids in polyphosphoric acid.The reaction process was influenced by the molecular chain length of dibasic acids.When the molecular chain length of dibasic acids was too short,the reaction process was hindered,and colored product was given out because of much sidereaction.The optimum reaction time and temperature were investigated.High molecular weight condensation polymers of dibenzo-18-crown 6 with sebacic acid were produced by controlling of the reaction conditions,which were good film-forming material.
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发布时间：2021-03-19 - 摘要：The effect of temperature on the friction wear properties of a kind of liner Polyimide (YS-20) and a kind of crosslinked Polyimide (KH-304) was studied using a pin on disc wear tester.The test results showed that with sliding time increasing,friction coefficient of YS-20 increased to a maximum then decreased to steady value,but that of KH-304 decreased directly to steady value.For a steady value of friction coefficient,with temperature increasing,the friction coefficient of YS-20 increased to a maximum value then decreased,but that of KH-304 decreased directly to steady value.Wear rate of the both Polyimides (PIs) increased with temperature increasing.The wear rate of KH-304 was higher than that of YS-20 under the same temperature.Scanning Electron Micrograph (SEM) analysis indicated that with temperature elevating,debris of YS-20 appearances changed obviously,but that of KH-304 varied little.Fourier Transform infrared Spectrometer (FTIR) indicated that the tribochemical reaction of KH-304 occurred more obviously than that of YS-20.The analysis above suggest that the surface layer of the linear PI changed from glassy body, to elastomer and then to melting body.Tribochemical reaction occurred at the surface of the crosslinked PI,which effect the friction-wear properties of the linear PI and crosslinked PI respectively.
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发布时间：2021-03-19 - 摘要：A biodegrable hydrogel based on α,β poly DL asparamide was synthesized by polycondensation of DL aspartic acid and 85% phosphoric acid in vacuity at 180℃,and then by ring opening reaction with 2 aminoethanol together with crosslinking reaction with 1,4 butanediamine. The swelling behavior of the gel in several solutions was investigated.The result shows that the swelling ratio of the gel in distilled water is 110～440,and it decreases differently in different concentration of electrolyte solutions.The swelling ratio in 0.16 mol/L 5-Fu solution can reach 140.Effect of molecular weight of polysuccinimide、amount of solvent and crosslinking agent on the swelling behavior of the gel was also studied.
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发布时间：2021-03-19 - 摘要：Chitosan is one kind of important nature polymer.There are amino groups (—NH2) in the chitosan chains.It can be dissolved in acid aqueous solution,which lead to —NH + 3 groups formation,and displays the anionic polyelectrolyte property.The macromolecule chains are stretched caused by electrostatic repulsion of the groups —NH+3 on the chains.The stretched chains will tend to be coiled with addition of salt because of the charge screening effect of added salt.Since the determination of the intrinsic viscosity of polyelectrolyte is an effective method to study the sensibility of polyelectrolyte to the addition of salt,the dilute solution viscosity of three chitosan samples with molecular weight (Mv=2.6×105,5.6×105 and 1.06×106) was measured both in solutions of NaCl with different ionic strengths (0.01,0.03,0.06 and 0.10mol/L) and in those of NaCl,KCl,CaCl2 and BaCl2 with the same ionic strength(0.06mol/L) respectively.All the viscosity measurement is proceeded by a dilute type Ubbelohde viscometer at 308.15K.The intrinsic viscosity of chitosan is found to be a linear function of 1/I(I is the ionic strength).It is also found that the response of the intrinsic viscosity of chitosan to the added salts proceeds in the order of anion Na+>K+>Ba2+>Ca2+.Accroding to the comparison of the ionic radius and hydrate number among the four anions,it displays that the influence of intrinsic viscosity of chitosan on the added salt is due to both the anion redius and anion solvent power.Meanwhile the parameter α of Mar-Houwink equation is estimated to be 0.78,0.70,0.67 and 0.62 in corresponding added salt ionic strength(0.01,0.03,0.06 and 0.10mil/L).They are all larger than 0.5,the value common to Gaussian coils in θ-solvent.According to all hydrodynamic theories,the high α-value must indicate that the chitosan chain is very extended in aqueous of relative stiffness of Smidsrod equation,the value of empirical parameter B, which is a measure of relative stiffness of different polymer chains,is found to be 0.074.Parameter B can also be used as a measure of the sensibility of polymer to the added salt.Compared with the date of other polymers in literature,in can be concluded that the chitosan has a higher chain-stiffness and a better resistance ability to the added salt.
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发布时间：2021-03-19 - 摘要：A series of toughening agents(LCEU-PPG) containing the polypropylene glycol(PPG) flexible space,mesomorphic unit,and reactive urea terminated group were synthesized and used to modify the epoxy resin E51/dicyandiamine(E51/dicy) curing system.The curing reactivity,dynamic mechanical behavior,and impact strength of the modified curing systems were investigated.The results show that the addition of LCEU PPG has improved the impact strength for 3～7 times;has accelerated the curing reaction apparently,leading to the reduction of apparent curing reaction energy (Ea) by 50～70KJ/mol and the fall of curing reaction temperature by 30～40℃.Elastic modulus are almost equal to or higher than that of the unmodified system,although Tg is slightly decreased and β-transition temperature is shifted to a lower temoerature.
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发布时间：2021-03-19 - 摘要：The effect of some metal cations on the gel content of epoxy ACM and the mechanism of ring opening of epoxy group under the catalysis of polyvalency metal cations were studied.The results show that the gel content of epoxy ACM was increased with the positive charge of metal cations and the catalyzing abilities of metal cations to open epoxy group were in following order Fe3+ >Al3+ >Fe2+ >Mg2+ >ca2+ ≈Na+.These phenomena agreed with both the acidic dissociation constant ( K 1) of hydration cations and the epoxy-opening mechanism catalyzing by metal cations.Based on the relationship of [η]～Mηestablished in polyethylacrylate,through proximate calculation,the critical value of ring-opened number of epoxy group in copolymer at which the gel content of copolymer was less than 1% were obtained.
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发布时间：2021-03-19 - 摘要：In the rubbery state of amorphous polymers under uni axial drawing,the glolal chain orientation will relax in orders of magnitude slower than the relaxation of local segmental orientation.When this state of hot drawn sample is frozen at temperatures lower than its glass transition, Tg,an amorphous state with high global chain orientation but nearly random segmental orientation(GOLR) would result.The characteristic features of GOLR state are large recovery of the elastic deformation β ′ of global chain on being heated to temperatures above Tg(β′=70%～90%) and very small birefringence(△n～10-4).The effect of global chain orientation (GCO) on crystallization behavior of amorphous polyethylent terephthalate (PET) fibres is studied by differential scanning calorimetry (DSC) performed at different heating rates and solvent induced crystallization (SINC) method by comparing the crystallization behavior of PET as-spun fiber in GOLR state(β ′=34.3%,△n=1×10-3,ρ=1.3362g/cm3 with that of its thermally relaxed (105℃,3min in the air) PET sample(β ′=5.4%,ρ=1.3362g/cm3).The results indicate that the cold crystallization temperature,Tcc,is effectively depressed by the GCO.That means the global chain orientation accelerates the development of crystallization.
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发布时间：2021-03-19
Research Article
- 摘要：The self reinforcement of low density polyethylene (LDPE) in the oscillating stress field under low pressure was studied.With the orthogonal statistical analysis method,the optimum processing parameters have been found.The tensile strength of LDPE increased from 10 MPa of ordinary products to 21*!MPa of self reinforced specimen.The DSC and X-ray investigation indicates that the enhancement of tensile strength is due to the high degree orientation of macromolecule along flow direction and the crystalline refinery.The self-reinforced LDPE is more transparent than ordinary LDPE specimen due to crystalline refinery.The specimen breaks by tensile in a ductile manner,the toughness and elongation has not decreased with the increase of tensile strength.
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发布时间：2021-03-19 - 摘要：The composition,structure and cyclic ratio of diallyl dibenzoxazine (DADBOZ) prepared by suspension method were characterized by FTIR and 1H-NMR.A combination of DTA,FTIR was used to investigate the curing reaction of DADBOZ precursor at different conditions.The DADBOZ precursor is composed of two kinds of reactive functional groups:one is benzoxazine ring and another is allyl group,which can be cured through ring opening polymerization or addition polymerization at different situation,Therefore,differnt polymer structures can be obtained.
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发布时间：2021-03-19 - 摘要：The Poly(ethyl terephthalate) (PET) surfaces were modified by fluorocarbon plasmas.Angle dependent x ray photoelectron spectroscopy (XPS) and contact angle techniques were employed to determine the change of the surface structures and properties of the modified PET.Experiments show that the changing of F/C ratio and contact angle of the modified PET along with the CH 4/CF4 feed.It was found that the modified surfaces show more hydrophobic,and CF 4/CH 4 plasma exhibits more stronger hydrophobic effect than CF4plasmas alone.The structures and properties of the modified PET surface depend on the molar ratio of the CH4/CF4 feed.The plots of contact angle vs.molar ratio of the CH4/CF4 feed is the same with that of F/C ratio measured by angle-dependent XPS at 10 degree of taking-off angle.By conparison,the relationship of the sampling depth of XPS and contact angle can be obtained.
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发布时间：2021-03-19 - 摘要：MAH is grafted on PP powder surface by photoinitiated solid phase graft copolymerization with BP or MK as photosensitizer.The grafting degree,which is influenced by factors of the concentration of photosensitizer,reaction temperature,irradiation time,and surface treatment of PP is studied.The grafting extent and crystal structure of MAH_gPP are characterized by XPS,WAXD and FT IR.Results indicated the grafting degree increases with the concentration of MK,the preferred reaction temperature is 24℃.After plasma treating and the first-grafting of PP surface,the adsorption of the monomer on PP surface increases.The contact state between the monomer and PP macromolecule is improved and the grafting degree is increased also.
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发布时间：2021-03-19 - 摘要：The produce process and characteristics of Cross linked PSU membrane were studied. The metalation is introduced in the PSU to make the sulfinated and sulfonated PSU, followed by the partial oxidation and cross linking, the ion exchanged PSU membrane is prepared. The results on swelling and resistance, permselectivity and thermal stability were obtained which show that the cross linked PSU membranes have small swelling, lower resistance, good permselectivity and thermal stabiity.
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发布时间：2021-03-19 - 摘要：Copolymerization of ethylene/1 octene with three ansa zirconocene/MAO catalyst systems were investigated. The polymerization activity is dependent upon the influence of electronic effects. It decreases in the following order: C6H4(CH2)2Cp2ZrCl2> C5H3N(CH2)2Cp2ZrCl2 > CH3N(CH2)2ZrCl2. The composition and sequence distribution of copolymer were calculated from 13 C NMR spectra. It was found that the activityes of three ansacatalysts were lower than Et(Ind) 2ZrCl2 under the same 1-octeone concentration.And their copolymer had lower 1-octene incorporation than that of Et(Ind)2ZrCl2 under the same 1-octeone concentration.And their copolymer and lower 1-octene incorporation than that of Er(Ind)2ZrCl2.Other properties such as molecular wieght,melting point of copolymer were compared.
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发布时间：2021-03-19 - 摘要：A series of random copolymers composed of polyetherketoneketone (PEKK) and polyethersulfoneetherketoneketone(PESEKK) containing naphthalene ring were prepared by low temperature solution polycondensation of 4,4′- bis( β- naphthoxy) diphenylsulfone(BNODPS), diphenylether(DPE) and terephthaloyl choride (TPC) in 1,2 dichloroethane and in the presence of AlCl 3 and NMP. Some properties of the copolymers were investigated by DSC, TG, WAXD, etc.. The results show that the T g of the copolymer is higher than that of pure PEKK,the melting temperature and the crystallinity of the copolymer decrease with increasing of PESEKK unit contents.the copolymers have good heat resistance and excellent chemical resistance.
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发布时间：2021-03-19 - 摘要：Through asymmetric hydrosilylation of poly(isopropenyl methyl ketone) and poly(mesityl oxide), poly(3-methyl 3-buten 2ol) and poly(4,4 dimethyl 3 buten 2 ol) with chiral alcohol groups were synthesized catalyzed by in situ catalysts prepared with chiral ligand, 2 (2-pyridyl) 4 carbomethoxy 1,3 thiazolidine, and [Rh(COD)Cl] 2. The asymmetric hydrosilylation of copolymers of isopropenyl methyl ketone or mesityl oxide with styrene (molar ratio 1∶1) was also investigated. The reactivity of these two homopolymers was lower than that of poly(methyl vinyl ketone) as the result of steric effect of methyl group.The effect of solvent on the optical rotations of the products was studied.It was found that the optical rotation was mainly caused by the chiral side alcohol group.
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发布时间：2021-03-19 - 摘要：The photopolymerization of acrylonitrile(AN) sensitized by N-acrylyl phenothiazine(APT) and its oxides, i.e. N acrylyl phenothiazine sulfoxide(APTO) and N acrylyl phenothiazine sulfdioxide(APTDO) was studied kinetically. It was found that the photopolymerization rate equations and E a were obtained as following: Rp ∝ 0.44 0.84 , Ea =23.23kJ/mol; R p ∝ 0.44 0.87 , E a =22.97kJ/mol; R p ∝ 0.47 0.88 , E a= 22.33kJ/mol.From the UV analysis for P(AN) sensitized byAPTO, it was confirmed that APTO not only sensitized the photopolymerization of AN but also entered into the P(AN) chains.
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发布时间：2021-03-19 - 摘要：Fe3O4/P(St NIPAM) thermosensitive magnetic microspheres with core/shell structure were prepared by copolymerization of styrene(St) and N isopropylacrylamide(NIPAM) in the presence of Fe3O4 magnetic fluid in ethanol/water medium. The content of Fe3O4 is about 20～100mg/g in the microspheres. The hydrodynamic diameter of Fe3O4/ P(St NIPAM) is depended on temperature and shrank above the lower critical solution temperature (LCST) in water. Thermosensitive magnetic microspheres with average diameter size range from 5 to 100μm were obtained by different reaction conditions.Higher initiator concentration formed larger Fe3O4/P(St-NIPAM) microshpheres,Ethanol played important roles in the polymerization,while the stabilizer PEG has smaller effrct for the size of Fe3O4/P(St-NIPAM) microspheres.
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发布时间：2021-03-19 - 摘要：The contact charge transfer (CCT) complex can be formed between poly(propylene oxide)(PPO) as an electron donor and oxygen as an electron acceptor.A reversible CCT absorption appears at 226 4nm due to their very weak combination.The result shows that without initiator and in the dark,the oxidation of PPO goes through the initial state of O2 CCT as same as the oxidation of its model compound isopropyl ether.It is proposed that the initial dark oxidation of PPO undergoes through O2 CCT,CTC,H + transfer,free radicals in cage,and the formation of hydroperoxide.The hydroperxide is the primary product of dank oxidation and its subsequent decomposition results in the chain cleavage with decrease of the molecular weight of PPO.
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发布时间：2021-03-19
Research Bulletin
- 摘要：Atactic polystyrenes with molecular weights from 460 to 1550000 were studied by calorimetric measurement.It was found that the samples having molecular weight higher than 103 produce initial DSC heating traces with well defined endothermic peaks in the vicinity of T g,the peak size decreased with the increase of molecular weight and then disappeared on rescanning.However,for the samples with molecular weights less than 103 no endotherm was observed in the same measurement conditions.The endothermic peaks in DSC traces suggest the existence of localised regions of segmental order in the samples and its possible origin must be the contribution of rr sequence in chains,because these samples have the different steric structures.13C-NMR determination indicates the proportion of rr triads is lower than 20% for samples of Mn3 and larger than 30% for those of Mn>103.Atactic polystyrenes used in the study were synthesised by solution polymerisation with nbutyllithium as initiator,benzene as solvent and alcohol as precipitant .The polymer concentrations were about 1～2% at the end of polymerisation.
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发布时间：2021-03-19
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